Transcript Undulator Fiducialization Procedure

LCLS Undulator Fiducialization
1
LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Outline
Fiducialization Procedure
Capacitor sensors
Cam movers
Pointed Magnets
Test Results
Fiducialization Errors
Summary
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Fiducialization Procedure
Goal to find position of undulator axis with respect to mechanical references. Based on
results of magnetic measurements. Magnetic measurements, tuning, and fiducialization is
one procedure.
1. Alignment to the bench. First step - by conventional tools (±0.2mm); second with the
use of capacitor sensors (±10µm). Reference plates for initial alignment to the bench and
as capacitor sensor home positions (ordered). Position adjustments with cam movers.
2. Hall probe measurements to find magnetic axis, i.e. magnetic reference (±5µm random
error). Final pitch and yaw corrections.
3. Coordinate transfer from magnetic to mechanical references. Pointed magnets as
intermediate reference. Offset between magnetic axis and PM center by bench stage
encoders. (Probe centering ±1µm in Y and ±3µm in X). Distance from PM center to PM
tooling balls is known from PM calibration. CMM for mechanical measurements (±15µm).
Y
Z
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Fiducialization Procedure (cont.)
Set-up on the bench
Cam movers
Pointed Magnets
Hall probe
Stages
X,Y,Z
Granite table
Undulator support
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Capacitor sensor fixture
Goniometer
Macor ceramic rod
G-10 Arm
X, Y, Z
Y-stage
6 HPB-150 Capacitec sensors
(amplifier card Model 4100-SL)
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Capacitor sensor measurements
u/2
17000 x 6
data
A/D Converter
6 channels
Simultaneously
IOtech ADC 488
Start position
First minimum
Triggers from
Z - Stage encoder
Every 200 µm
10 Points - ?
window
Z - positions of minimums
and voltages for 4 channels
Calculation of X,Y,
Roll, Pitch, Yaw.
(Gap, cant angle - ?)
Make decision
Position corrections
by cam movers
Apply Calibration
~10mV/µm
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Cam Mover Design
Bearing
Cam
Brake
Potentiometer
(Novotechnik P6500 Series)
Stepper Motor
(Compumotor LN Series)
Harmonic Drive
(1:120)
*G. Bowden “Roller Cam Positioners.” LCLS-TN-05-?
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Cam movers
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Single Cam Mover test set-up
Mitutoyo linear gage
0.5µm resolution
Cam mover
100 lbs
Table
5
1
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Single Cam Mover Test Results
Cam backlash measurements
Cam Mover Lift Range
5
800
(200 Motor steps correspond to 20µm lift)
4
600
3
200
2
~ 1 Revolution
Backlash in µm
Cam lift in µm
400
0.725mm
0
-200
1
0
-1
-2
-400
-3
-4
-600
-5
0
-800
0
25
50
75
100
20
40
60
80
100
120
140
160
180
200
220
Motor step number
125
Number of motor revolutions
4
Cam Resolution
Cam lift in µm
3
2
Cam Resolution ≈ 0.2µm / motor step
1
0
5
10
Step number
15
20
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Cam Mover system test set-up
Y2
Yaw
X2
Y
Z
5
4
X
0
Y1
Pitch
X1
Roll
3
2
1
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Cam Absolute Positioning
N
x=100µm
y=100µm
x=400µm
y=400µm
x=900µm
y=0µm
x=0µm
y=700µm
1
-3
5
-15
21
-20
34
-9
-37
2
0
0
-1
-1
-2
5
2
15
3
1
-1
0
-2
0
0
0
-3
4
1
-1
0
-1
0
0
0
-3
5
0
0
0
0
0
0
0
0
x
y
= f(>20 mechanical parameters)
Cam Number
Cam Offset(750µm nominal)
1
2
3
4
5
746
742
738
759
725
Feedback system : Capacitor sensors or Linear gages at MMF
HLS + WPS or BBA in the tunnel
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Hall probe measurements
Goal is to find the undulator magnetic axis
Scan in X at different Z positions
Scan in Y at different Z positions
Find undulator center for each Z position. Have a set of points along Z
direction.
Make linear fit for all points along Z. Make corrections for pitch and yaw
angles if necessary. The undulator is aligned to the bench.
Apply shims to make trajectory straight and correct phase errors.
Scan in Z at different X and Y positions. Calculate K vs. Y and K vs. X.
Find where K is nominal. This is the position of the axis. Leave Hall probe
in that position. Take readings from stages.
Based on Hall Probe noise and our best experience
the accuracy will be ±5µm
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Pointed Magnet Fixture
Transfer coordinates from the undulator magnetic axis to mechanical reference
Tooling Balls
Needles
Permanent Magnet
Frame
Goal:
Find distances from magnetic center to tooling balls.
Problem: Accuracy of probe centering depends on PM misalignment.
Solution: Adequate two-point measurement algorithm.
* I. Vasserman Quadrupole magnetic center definition using the hall probe measurement technique.
APS-Pub. LS-285, Argonne, 2004
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Hall probe centering accuracy
Starting from random positions (±0.2mm) from center, scan in X and Y.
Differences in centering results w.r.t. first scan shown.
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Hall Probe centering
(20 scans)
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Y position in µm
3
2
1
0
-1
± 5 µm
-2
-3
Std (in X)= 3µm
-4
-5
-30
-20
-10
0
10
20
30
X position in µm
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Pointed Magnet Calibration
D/2
Δy
D
2Δy
A1,2 = D/2 ± Δy
Sentron 2-D XZM12 Hall probe
Newport X-Y, model 406, stages with CMA-12CCCL
actuators and ESP-300 controller
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Calibration Test Results
50
Offset between magnetic and
mechanical centers
(Calibration results in Y-direction)
49
48
Do centering in one position
Rotate fixture at 180˚
Do centering in second position
Calculate offset
Offset in µm
47
46
1µm
45
44
43
Calibration accuracy = 1µm in Y,
3µm in X
42
41
40
0
5
10
15
20
Calibration number
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Fiducialization Errors
Total Fiducialization error includes the following components:
Finding undulator magnetic axis
~ 5µm
Hall probe centering
~ 1µm
Pointed magnet calibration
~ 3µm
Tooling ball eccentricity
= 5µm
CMM measurement
~ 15µm
Other possible errors
~ ? (10µm)
Total:
20 µm
Fiducialization error budget*:
Vertical:
40µm
Horizontal:
50µm
* LCLS Parameters Database/Undulator-System (PRD 1.4-001-r3)
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Summary
Fiducialization procedure has been finalized.
Capacitor sensors are ready for measurements (designed, machined,
assembled, and tested).
Pointed magnets and PM calibration fixture have been developed, fabricated,
and tested.
Adequate measurement algorithm has been proposed and tested.
Cam mover and support system is ready.
Fiducialization accuracy is expected to be ~ 20 µm.
We are ready to start working with the undulator prototype
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
End of presentation
Thank you!
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
PM mounting
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Two-Point Measurement Algorithm
N
Zero field line
By= 0
Y
0
Error
X
500
0.11
Magnetic Field
B vs.v.sXDistance
Mechanical
center
atfrom
0.2mm
from the
needle tip
400
0.1099
300
0.1098
200
0.1097
B(T)
B
(G)
100
0.1096
0.1095
0
N
0.1094
-100
0.1093
-200
dB/dY = 1G/µm
0.1092
-300
0.1091
-400
0.109
-500
-0.2
-300
-200 -0.1-100
00
0.1
100
Position in
in µm
mm
Position
200 0.2 300
0.3
400
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515
Tolerances
* Alignment error budget:
Vertical
Horizontal
Longitudinal
Roll
Pitch
Yaw
-
70µm
180µm
1mm
1 mrad
80µrad
240µrad
Do the best!
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LCLS Undulator Fiducialization
Yurii Levashov
October 20, 2005
[email protected]
*Work supported in part by DOE Contract DE-AC02-76SF00515